This utility model relates to a mirror operating mechanism comprising a first mirror which is a half mirror adapted to separate a light beam from a photographing lens into a reflected light beam and a transmitted light beam and a second mirror which is a total reflection mirror adapted to reflect a light beam passed through the first mirror.
It is essential for a mirror operating mechanism for instance, in an automatic focus detecting device using a half mirror and a total reflection mirror, to introduce a light beam forming the image of an object to be photographed to a finder system and a focus detecting system simultaneously so that the light beam will form the image of the same object on the focusing screen in the finder system and on the focus detecting element in the focus detecting system. Furthermore, it is necessary that during the photographing operation the mirrors are retracted from the optical path in the photographing plane to prevent the occurrence of vignetting on the film surface, and when the mirrors are moved upwardly, the transmitted light beam passing window should be covered to prevent the formation of ghosts due to the leakage of light from the finder system and the reflection of light from the focusing screen. In addition, it is necessary to adjust the angle of the total reflection mirror to adjust the formation of an image on the focus detecting element.
In view of the foregoing, an object of this utility model is to provide a mirror operating mechanism which can satisfy all of the above-described requirements with a simple construction.